“Demon”

It was always “demon” (spelled daemon or dæmon), as in a spiritual attendant. Christian mythology has poisoned the word, and anyone who says “daymon” to not offend them is a coward.

See here:

https://www.merriam-webster.com/dictionary/demon

Edit: When I say it was always pronounced “demon”, I mean the nerds who started calling a small background program daemon pronounced it “demon”.